Apparatus for decurling a web



Dec. 29, 1959 I P. zERNov 2,918,897

APPARATUS FOR DECURLING A WEB Filed'July 2s, 1958 2 sheets-sheet 1 PETER ZERNUV Dec. 29, 1959 P, ZERNOV APPARATUS FOR DECURLING A WEB 2 Sheets-Sheet 2 Filed July 28, 195e '5g je INVENTOR. PETER ZERNDV BY M%,M 7,ea

APPARATUS FOR DECURLING A WEB Peter lzernov, Milwaukee, Wis., assignor to Mercury Engineering Corporation, Milwaukee, Wis., a corporation of Wisconsin Application July 28, 1958, Serial No. 751,358

3 Claims. (Cl. 118-124) This invention relates to paper fabricating apparatus and more particularly to means for conditioning a paper web before it is led to a blanking press or other apparatus for subsequent operation thereto. This invention nds particular utility in decurling a web containing printed matter or having a wax coating or the like on its surface.

`Conventional decurlers such as those comprising a sharp-edged bar for a decurling surface are not entirely suitable for bearing against that side of a Web which is coated or contains printed matter, because the edge of the bar tends to scratch and remove part of the material from the surface.

Decurlers having a round cross section, for example cylindrical rollers, have been proposed to overcome this difficulty but these devices have not been satisfactory either. Heretofore these attempts to overcome this problem have not proved satisfactory because these rollers were too large in diameter to elfectively perform the decurling operation. Smaller diameter rollers have heretofore not been used successfully because of the deflection of these smaller rollers along their length. Because of this deflection, the amount of decurl across the width of the web is not uniform. For example, because of the short distance between the nips of the pairs of feed rolls where these decurlers are located and Where the web is under tension, if there is a slight deflection of the decurling roller the amount of decurl across the web will vary greatly due to the fact that this tension is all absorbed at the location where the web is tight, that is, where the roller is no deflected.

It is accordingly an object of the present invention to provide a roller decurling unit which effectively acts to decurl a tensioned web and overcomes the above mentioned dil'l'iculties with and shortcomings of conventional deourlers.

More particularly the present invention provides a roller type decurler of small diameter and having means for preventing deliection thereof. Theseand other objects and advantages of the present invention will become more apparent as thisv disclosure progresses, reference being had to the accompanying drawings, in which, .Y

Figure lis a schematic general side elevational view of a decurler unit embodying the invention;

Figure 2 is a front elevational view of the decurler unit shown in Figure 1 and taken generally alongline 2 2, but on an enlarged scale and certain parts being broken away;

Figure 3 isa'plan view vofthe unit shown in Figure 2 with parts broken away and shown in section;

Figure 4 is a detailed sectional view taken on line 4-4 of Figure 2;

Figure 5 is a fragmentary detailed sectional view taken on the line 5-5 of Figure 4;

Figure 6 is an elevational view in section taken along line 6 6 in Figure 2.

Referring in greater detail to the drawings, ,and particularly Figure 1, the paper web W is pulled olf of the usual United States Patent O ICC supply roll S by setsv of feed in rolls 14 and 15 and a set of feed out or delivery rolls 16 and 17, which rolls are suitably journalled in the frame F in spaced relation to each other. The web is then advanced to another set of rolls R1 and R2 which feed the web to a die-cutting or blank forming press or other paper web fabricating apparatus. The web is decurled as it passes through the feed rolls 14-17 as hereinafter described.

The rolls 14, 15 and 17 are all of the same diameter, but the roll 16 is of slightly larger diameter so that there is a speed differential between the sets of rolls so that the rolls 16 and 17 tend to feed the web -between them at a faster rate than the web is supplied to them by the rolls 14 and 15 and thus act to tension the web between said sets of rolls.

The rolls 15 and 17 may be of any diameter and not the same as 14 because they are not the driving rolls.

The rolls 14 and 16 are positively driven by a gear 20 on the shaft of each roll meshing with a common drive gear 21 on a shaft 22 journalled in the frame F and carrying a worm gear 23 driven by a Worm 24 on the drive shaft 25 of a variable speed hydraulic motor 26 of conventional design.

For moving the rolls 15 and 17 relative to the rolls 14 and 16, in each instance an air cylinder 27 has the rod of its piston 28 engaging one of the supporting arms, 18 for its associated roll 15 or 17. Each piston 28 may be initially loaded by a spring 29 to offset the greater portion of the weight of the roll assembly. Each cylinder 27 is supplied with air under pressure by branch pipes 30 connecting with a pressure supply pipe 31. Each branch pipe 3i) has a pressure gauge 30a therein and an adjustable pressure relief valve 32 so that the air pressures acting on the pistons 28 will act to move and hold the rolls 15 and 17 against the web W under variable pressures determined by the adjustment of the relief valves 32 to vary the bite or nip between the spaced sets of feed rolls above mentioned and the web. It has been found that the best results are secured when one of the sets of rolls 15, 17 or 14 and 16 is allowed to slip so that the nipping pressure applied to one set of the rolls mentioned is less than the other.

For decurling the web, the spaced cold ironers 33 and 33a are mounted on slide mounting means in the form of slide blocks 34, 34a respectively, which blocks are rigidly secured together by a connecting rod 34b and are vertically slidably mounted and guided in slots 35 inthe side sections of the frame F. The decurler members 33 and 33a are vertically adjustable relative to the sets of rolls 14, 15 and 16, 17 by a chain 36 whose ends are secured to each block and which is trained over spaced sprockets 37 and 38. The sprockets 38 are carried by a cross shaft 39 journalled in the spaced side members of the frame F while the sprockets 37 are separately journalled to said side frame members. One of the sprockets 37 has its shaft connected with aworrn wheel 40 which meshes with a Worm 41 on a shaft 42 provided with a hand wheel 43. Turning the wheel 43 will act through the chains and sprockets above described to move the blocks 34 and 34a together up or down in the frame F to the desired position.

. The member 33 is a square bar positioned to` present its corner edge to the unprinted or uncoated side of the web and is spaced apart from the roller member 33a so that one of the members cooperates with the feed rollers to iron or smoothly crease the web in one direction, and the other member acts to iron or smoothly crease the web in the other direction, to thereby put a reverse curl in the web from that which have been produced by winding up the web on the supply roll. Since the web W is fed from one set of feed rolls to the other, and one of ythe decurler members 33 or 33a engages a side of the web as it is fed under tension over this member to produce a reverse curl, the initial curl is taken out of the web. Unless tension is applied to the web during decurling, breaks or ridges will be produced in the surface of the web, and the speed differential between the sets of rolls produces enough tension in the web as it passes over the ironer to form a smooth reverse curl. The adjustment of the variable relief valves 32, so that the nipping pressure of one set of rolls is greater than that of the other, provides a means for varying the amount of Ltension exerted on the web as it passes over the ironer bet-Ween the sets of rolls 15, 17 and 14, 16. The position of the active member 33 or 33a relative to the feed rolls may be varied from time to time to vary the amount of decurl by the operators operation of the hand wheel 43.

In accordance with the present invention, the roller decurler or ironer 33a is comprised of a relatively small diameter roll 45 which is journalled at each end in antifriction bearing assemblies 46 carried in the end plates 47. Each plate 47 has the generally square block 34a welded thereto, which blocks as previously mentioned are adapted to fit securely but replaceably into their slots 35 in the frame F. A large and rigid cross bar Si? rigidly secures the blocks 34a together by extending between them and being fastened thereto by the cap bolts i and pin 52 connections.

To be effective in properly decurling the web, the roller 45 must be of small diameter, and a roll as small as three-fourths of an inch in diameter has proved to be satisfactory in practice, although the use of even smaller diameter rolls, such as for example, three-eighths of an inch in diameter, is contemplated with the present invention.

Means are provided for backing up this small diameter roller to prevent any detiection thereof as the tensioned web moves rapidly over this roller. This backing means takes the form of a plurality of pairs of anti-friction rollers 53, 54, which pairs are spaced along the length of the roll 45. The rollers 53, 54 are of the type having a ball bearing assembly A on which they are mounted on a short shaft 55.

The rollers 53, 54 are rotatably mounted on shafts 55 which in turn are secured to their bracket 56 by the nuts 57. Each bracket 56 is welded to a mounting plate 58 which in turn is rigidly secured by cap bolts 59 and locating pins 60. Suitable shirns (not shown) may be provided between the mounting plate 5S and the cross bar 50 to insure accurate alignment of the pairs of backup rollers and consequent deflection-free rotation of the roll 45.

The criticality of the roller-deflection can be better appreciated when it is realized that a detlection of the roller of only 0.010 of an inch will cause the amount of decurl to vary greatly along the length of the roll. It is this deflection problem that has limited the use of rollers as decurl surfaces.

With the present arrangement, the same small roller can be used for decurling webs of various thicknesses. For example, in decurling a relatively thin web, lthe roller as shown in Figure 4, would be positioned lower to thereby cause the web to move or bend over a greater angle in passing the roller, than for a thicker web wherein less of an angle would be necessary and the roller would be raised to a higher position.

If the web to be decurled contains printed matter on both sides, the decurler on each side of the web would be of this roller type. This conversion may be easily effected by substituting another roller decurler unit 33a for the square bar type of unit 33. When thus mounted in the frame F for contacting the lower side of the web, the unit 33a would, of course, be turned 180 degrees from the position shown in Figure 4 for the upper roller unit.

By feeding the web through the rollers as shown in Figure 4, that is, carrying the web around a substantial portion of the periphery of the rollers before its contact with the decurler roller, the tendency for wrinkles to develop in the web has been eliminated. This arises because of the fact that the web has a chance to align itself on the rollers before it engages the decurler roller and the result is substantially complete elimination of wrinkles in the decurled web.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

I claim:

1. In a paper fabricating apparatus for conditioning the web after leaving its supply roll and prior to another operation thereon, said apparatus having means for producing tension in a portion of said web, the improvement residing in a rigid support including a bar extending across said portion and adjustable relative thereto, a decurler roller rotatably mounted in said support for contacting said web portion and of such diameter so as to deflect under tension of said web when unsupported along its length, and pairs of anti-friction rollers rotatably mounted at spaced locations along the length of said bar and engaging said decurler roller between said rollers of each pair and opposite to said web portion to prevent deflection of said roller as the web urges the latter against said pairs of rollers.

2. A decurler assembly for decurling a tensioned web, said assembly comprising a rigid support adapted to extend across said web, a rod rotatably mounted at each end in anti-friction bearings carried by said support, and pairs of complementary anti-friction support rollers secured to said support at spaced locations along the length thereof, said rod being between the rollers of each pair, said rollers being in axial alinement and engaging said rod at a location radially spaced from said web to prevent deection of said rod.

3. A decurler assembly for decuring a tensioned web, said assembly comprising a rigid support adapted to extend across said web, slide mounting means at each end of said assembly for slidably mounting the latter relative to said web, a rod rotatably mounted at each end in anti-friction bearings carried by said support, and pairs of complementary anti-friction support rollers secured to said support at spaced locations along the length thereof, said rod being between the rollers of each pair, said rollers being in axial alinement and engaging said rod at a location radially spaced from said web, to prevent deflection thereof as said web urges the latter against said rollers.

References Cited in the le of this patent UNITED STATES PATENTS Baumgartner Mar. 6, 1956 

